1. Field of the Invention
The present invention relates to a delivery system, a server device, a terminal device, and a delivery method.
2. Description of Related Art
Conventionally, as a method for distributing a software resource such as programs, contents, and settings, there are a push type method in which a server transmits the software resource and a pull type method (download type method) in which a terminal retrieves the software resource.
In the download type distribution method, there are advantages that the server does not need to know a power on/off state of the terminal and the terminal can retrieve the software resource at a convenient timing. This method is preferred when applying a latest modification program at all times, or when the terminal determines whether the modification program needs to be applied, and the like.
Japanese patent application laid-open No. 11-306000 relates to a method for keeping software installed in a medical device connected to a network at its latest version, and the Japanese patent application laid-open No. 11-306000 discloses a method in which the version of the software held in the server is compared with the version of the software installed in the device, and if the server has newer software, the software is downloaded, so that the software installed in the device is kept at its latest version.
Japanese patent application laid-open No. 2003-5991 discloses a system in which, to easily perform an update of firmware included in an electronic device, at a predetermined timing such as when the electronic device transmits an inquiry or when new firmware is added, a server notices the terminal of the version of the firmware held in the server, and the terminal downloads firmware from the server and installs the firmware when the terminal finds that the version is newer than the version of the firmware included in the terminal on the basis of the notice.
However, the conventional download type distribution method has a problem that whether the resource released from the server is applied depends on an operation in the terminal because the resource is applied at a timing such as when the terminal is started or when an update operation is performed in the terminal. In other words, the conventional method has a problem that it is difficult for the server to control the date and time of the update or check the distribution status, and a normal operation of the terminal is adversely affected because the resource is downloaded and applied when the terminal is in use.
For example, the conventional distribution methods described in the Japanese patent application laid-open No. 11-306000, the Japanese patent application laid-open No. 2003-5991, and the like, cause a problem that, when the size of the resource to be downloaded is large, a load due to the download is added to the network, and a normal operation of the terminal is affected. Therefore, although it can be considered that the download is performed in a time period when the terminal is not in a normal operation, such as a non-business time period, such a time period is usually late in the night or the like, and it is difficult to perform the download operation manually in the server or the terminal. On the other hand, although it can be considered that the download operation is performed automatically by, for example, changing the start time of the terminal using a scheduler which can control power supply of the terminal, a problem that a large amount of effort may be required to set the schedulers of all the terminals still remains.
In conventional distribution methods, although a method in which, when distributing resources, downloads are not allowed before a specific date and time is employed, this method has a problem that a long time is required until the resources are applied to all the terminals because the downloads concentrate at the specific date and time from many terminals at the same time and increase the load of the network.